Breech-closure.



No. 693,900. Patented Feb. 25,1902.

' H. .1. PERRY. I

BREECl-I. CLOSURE.

(Application filed June 19, 1901.)

(N0 Mo HERBERT JAS. PERRY, OF CHESHUNT, ENGLAND.

BREECH-CLOSURE.

SPECIFICATION formingpart of Letters Patent No. 693,900, dated February 25, 1902. Application fileddune 19, 1901- Serial No. 65,096. (No model.)

To all whom it ntay concern.-

Be it known that I, HERBERT J AS. PERRY, a subject of the King of Great Britain, residing at Waltham New Town, Waltham Gross, Cheshunt, in the county of Herts, England, have quick action is required and at the same time a large thread-surface to give the necessary strength.

The invention is more particularly applicable to the breech of quick-firing guns, the breech block or plug of which is generally secured in the breech by a short turn, causing sections of screws to engage. My invention provides a means by which the same action is effected; but a much larger effective surface of thread is provided, increasing the strength of the breech-closure. The invention, however, is also applicable to any case in which a quick action is required. I propose to make the thread of the screw in a series of steps, preferably three in number, in-

' creasing the diameter from the bottom successively to the top. The pitch of the thread in each step is exactly the same, so that as the diameter of the screw decreases from the top the angle of the thread becomes steeper. The difierence in diameter of each step'is such that when the screw or screwed plug is inserted in thesocket having internal threads to correspond the screw or plug can be dropped in until all the steps meet the corresponding steps in the socket, and a turn of the plug simultaneously engages all the threads. As the pitch in each case is the same a turn of the plug acts quickly upon every part of the screwand all the threads engage as if the plug were screw-threaded in the ordinary manner, although the extent of the movement is reduced in proportion to the number of steps employed.

In the accompanying drawings, forming part of this specification, in which like letters of reference designate corresponding parts in the several views, Figure l is a sectional view, with the plug part in elevation, of an internal screwed socket with the stepped plug in position; and Fig. 2 is an elevation of a second plug upon the same principle, but requiring a greater turn.

Referring to Fig. 1, A is the socket, having, as shown, the three internal screw-threads B, the hole decreasing in diameter with each step toward the bottom. Each step is thus an independent screw-thread of the same pitch and is not in any way tapered. The plug Q is correspondingly formed with the three steps D, each having a triple screw-thread of equal pitch to that of the socket. In this case a very rapid action is provided, as not only is the screw broken up into three steps, but a multiple thread is employed. This arrange+ ment is particularly applicable to the breech of a. quick-firing gun. No means are shown for turning the screw, as any of the ordinary methods employed can be used. Between each step a small space is left in the socket and plug, and the spaces E shown in the drawings between the ledges so formed can be packed with any suitable material.

The plug 0 shown in Fig. 2 differs from that in Fig. 1 only in the fact that the screw thread D is of smaller'pitch and is single, giving a less rapid action.

I do not in any way confine myself to the shape or proportions of the plug or screw, which may be varied according to the requirements, the rapidity of the action varying according to the pitch and number of threads.

The form of the screw-thread is also immatethreads increasing successively in diameter ence of the subscribing Witnesses, this 1st day' and corresponding to and adapted to engage of June, 1901.

the separate threads of the socket or breech r the said screw-threads being of the same HERBERF PERRY 5 width. Witnesses:

In testimony that I claim the foregoing as H. D. J AMESON,

my invention I have signed my name, in pres- A. NUTTING. 

